Mechanical, Structural, and Electrochemical Performance of Polyurethane Coatings for Corrosion Protection in Wind Energy Systems

Erosion of the leading edge is one of the most severe forms of damage in wind turbine blades, particularly in offshore wind farms. This degradation, mainly caused by rain, sand, and airborne particles through droplet impingement wear, significantly decreases blade aerodynamic efficiency and power output. Since blades, typically made of fiber-reinforced polymer composites, are the most expensive components of a turbine, developing protective coatings is essential. In this study, polyurethane (PU) composite coatings reinforced with titanium dioxide (TiO2) particles were added on glass fiber substrates by spray coating. The incorporation of TiO2 improved the mechanical and electrochemical performance of the PU coatings. FTIR and XRD confirmed that low TiO2 loadings (1 and 3 wt%) were well dispersed within the PU matrix due to hydrogen bonding between TiO2 –OH groups and PU –NH groups. The PU/TiO2 3% coating exhibited ~61% lower corrosion current density (I_corr) compared to neat PU, indicating superior corrosion resistance. Furthermore, uniform TiO2 dispersion resulted in statistically significant improvements (p < 0.05) in hardness, yield strength, elastic modulus, and adhesion strength. Overall, the PU/TiO2 coatings, particularly at 3 wt% loading, show strong potential as protective materials for wind turbine blades, given their enhanced mechanical integrity and corrosion resistance.